A conventional cleaning machine 10 at least includes a transportation apparatus 11 and a wash apparatus 12 as shown in FIG. 1. A plurality of electronic component trays P are fixed at the transportation apparatus 11, and mentioned transportation apparatus 11 is capable of delivering the electronic component trays P. Afterwards, the electronic component trays P can be cleaned by means of the wash apparatus 12. However, the clean method described above can not remove the tiny dirt distributed around the electronic component trays P so that the electronic components might be easily contaminated.